Insulation FAQ + Pros/Cons

This is part of a thread I started on the T4 forum. On the woes of insulation and deciding what to go with.  It looks at Rockwool, Sheepswool and Kingspan.   

ROCKWOOL aka normal Fibreglass Loft Insulation.

Pros

  • Cheap to buy from any DIY store.
  • Can be squeezed into gaps.
  • Better Sound Insulation that solid methods

Cons

  • Not very nice stuff – no proof that its bad for health but certainly bad for sanity when you get fibres on the skin.
  • Holds moisture unless a proper barrier is installed which prevents condensation from the inside of the metal skin soaking into the fibre.
  • Can be tricky to hold work with as it is a flexible material.

SHEEPSWOOL (alternatives are HEMP but see below).

Pros

  • Ecological.
  • Dries out pretty quickly given the right conditions.
  • Can be squeezed into gaps.
  • Better Sound Insulation that solid methods

Cons

  • More expensive – especially more than Rockwool.
  • Holds moisture unless a proper barrier is installed which prevents condensation from the inside of the metal skin soaking into the fibre.
  • Can be tricky to hold work with as it is a flexible material.

Interesting Information taken from Burdenson Sheeps Wool.

  • Sheeps wool insulation can absorb up to 33% of its own weight in moisture
  • Condensation control. Wool generates heat when it absorbs moisture from the air. When the air is saturated with water vapour, wool absorbs some 40% of its dry weight in moisture, producing 960 kilojoules of heat energy for every kilogram of dry wool. This warmth is not noticeable inside the building but it acts to prevent condensation in construction cavities by maintaining the temperature above the dew-point in damp
    conditions
  • Sheeps wool is hygroscopic, and can absorb and desorb water vapour without compromising its thermal efficiency. This makes it ideal for use in roofs and timber framed walls designed to avoid a damaging build-up of moisture by allowing water vapour to migrate through the structure.

Interesting Information taken from Burdenson Hemp Batterns.

  • They are not however suitable for cavity wall insulation, or under ground floor slabs. (I understand this is due to moisture properties)

Vapour Barrier

The problem of moisture collection for the above options can be reduced if a vapour barrier is fitted. This is normally in the form of Flashing Tape which is self adhesive and can be stuck onto the inside of panels before the insulation is fitted.

KINGSPAN aka rigid foil covered insulation.

Pros

  • Doesn’t absorb moisture.
  • Easy to fix in position.

Cons

  • More expensive – especially more than Kingswool.
  • No sound proofing to speak of.

Relative Warmths

(R values based on 50mm thickness – larger number better) – BIG THANKS DDIXONUK

  • Rockwool = 1.38
  • Sheepswool = 1.35
  • Kingspan = 2.17

Final Thoughts – There must be many other variations and alternatives. Is there one definitive right answer – I have NO idea!!

About CDB 362 Articles
Self-Employed Software Developer, Spark, Property Management, Hobby Forestry, Ex-Teacher, Engineering - Wood, Metal, Electrics & Computers. Outdoors - Walk, Cycle, Kitesurf,

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